The present invention is directed to a rolling protective shutter assemblies and, in particular, to an improved single-wall shutter slat with an integrated screw boss.
Rolling protective shutters are conventional and are used to provide protection against extreme weather conditions and to deter theft, for example. One such rolling protective shutter is disclosed in U.S. Pat. No. 4,345,635 to Solomon. As shown in FIGS. 1 and 2 of that patent, the Solomon shutter is composed of a plurality of elongated single-wall slats, each of which has a pair of circular ribs attached to its sides. The slats are interconnected by a plurality of elongate hinges, each of which has a pair of circular apertures in which the circular ribs of the slats are disposed. When the Solomon shutter is unrolled to its protective position, each of the slats in the shutter is disposed vertically with the ends of the slats disposed with guide channels or side tracks on either side of the opening. When not in use, the Solomon shutter may be rolled up into a housing disposed at the upper end of the protective shutter.
Another type of rolling protective shutter is disclosed in U.S. Pat. No. 5,365,990 to Ueda. As shown in FIGS. 2 and 3 of that patent, the Ueda shutter is composed of a plurality of double-wall slats, each of which has an upper rearward hook extending longitudinally along the upper edge of the slat and a lower U-shaped recess extending longitudinally along the lower edge of the slat. The recess has a forward horizontal projection on a rear edge and extending longitudinally so that when the lower slat moves down under gravity, the hook of the lower slat bears on the horizontal projection of the upper slat. The Ueda shutter may be rolled up and unrolled in a similar manner as the Solomon shutter.
In rolling shutter systems such as the Solomon and Ueda shutters, the slats of the shutter must be held in vertical alignment so that the shutter is properly deployed into and retracted from the side tracks without binding. In shutters formed by double-wall slats, such as the Ueda shutters, the slats are held in alignment by side plugs, such as the slide members in FIGS. 4 and 5 of the Ueda patent. An insert portion of a slide member is inserted into the hollow end portion of the slat, and the upper and lower blades of the slide member engage the ends of the adjoining slats. The slide members are inserted on both sides of the shutter to retain the slats in vertical alignment. Alternatively, some previous double-wall slats include screw bosses integrally formed within the hollow portions of the slats, with the side plugs being attached to the slats with screws or other fasteners that are inserted into the screw bosses. Due to the thickness of the double-wall slats, the side plugs can align the slats while fitting within the thickness of the slats and, therefore, do not increase the roll diameter of the shutter.
Conversely, single-wall slats, such as those in the Solomon patent, do not provide a hollow portion into which a side plug may be inserted or within which a screw boss can be integrally formed. Another example of a previously known single-wall slat is shown in FIG. 1. The slat 2 has a slat portion 4 with an elongated socket 6 integrally formed along one longitudinal edge 7 of the slat portion 4, and a rod 8 integrally formed along the other longitudinal edge 9 of the slat portion 4. To form a shutter curtain, a plurality of slats 2 are connected by inserting the rod 8 of one slat 2 into the socket 6 of the adjoining slat 2. This single-wall slat configuration permits the shutter curtain to be tightly wound around the shutter roll. As can be seen, the single-wall slat 2 does not provide a point of attachment for hardware that vertically aligns the interconnected slats 2.
One alternative for attaching alignment hardware involves integrally forming a screw boss on one of the surfaces of the slat portion 4 proximate either the socket 6 or the rod 8. After the shutter curtain is assembled, a screw and washer are attached to the slat 2 to engage the connected socket 6 and rod 8 to align the adjoining slats 2. This alternative aligns the slats 2, but the slat portion 4 is relatively thin and the screw head and/or the washer extend beyond the sides of the slat 2. The overhanging heads and/or washers may engage the shutter roll and the other attachment hardware such that the shutter curtain cannot be rolled up as tightly and, consequently, may require a larger shutter housing to enclose the rolled-up shutter curtain. Additionally, an external screw boss increases the amount of material used to form the slat and increases the cost of the slat.
Another alternative for attaching alignment hardware is shown in FIG. 2 and includes an additional assembly step of removing portions of the rods 8 at either end of the slats 2 to allow screws to be inserted into the ends of the sockets 6. After the slats 2 are cut to the proper length, a notch is cut in the slat portion 4 along the longitudinal edge 9 inwardly from the end proximate the point where the rod 8 is connected to the slat portion 6. The rod 8 is then cut to remove the end of the rod 8. After the slats 2 are assembled, screws are inserted into the ends of the sockets 6 without interference from the rods 8 and hold the slats 2 in vertical alignment. Screws are omitted from FIG. 2 for the sake of clarity. The shutter curtain may be assembled with screw heads that do not extend past the edges of the sockets 6 such that the curtain may be tightly wound on the shutter roll. However, the additional machining operations required to remove the ends of the rods 8 increase the cost of assembling each shutter curtain and increase the time required to assembly each shutter curtain, thereby reducing the throughput of the assembly facility.
Therefore, a need exists for an improved single-wall slat with an integrated screw boss that facilitates attachment of alignment hardware to the assembled shutter curtain without increasing the amount of space required to store the rolled shutter curtain and without increasing the cost of fabricating the slats and the of assembling the shutter curtain.
In double-wall slats, the open cavity of the slats provides an area for attaching alignment and retention hardware. For example, a screw boss can be formed within the cavity of the slat without affecting how tightly the shutter curtain is rolled. Another arrangement is shown in U.S. Pat. No. 5,253,694, issued to Bernardo. The Bernardo patent discloses an end retainer having a stem that is inserted into the cavity of a double-wall slat. The stem is secured to the slat with several rivets that penetrate an outer wall of the slat. The end retainer extends upwardly and downwardly beyond the cavity to engage and align the adjoining slats. The end retainer also has an outer flange that retains the ends of the slat within the side tracks of the rolling shutter.
To avoid increasing the storage space required for the rolled-up shutter curtain, the end retainers are shaped to match the contour of the slat so that the end retainer does not extend outwardly beyond the front and back walls of the slat. Consequently, a uniquely shaped end retainer is necessary to match the contour of a particular slat profile. Therefore, a need exists for a combination slat alignment and retention system that can be used with single- and double-wall slats of varying contours without increasing the storage space for the rolled up shutter curtain.